Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Fri Sep 08 2023 21:43:31

AWUS01 KWNH 082143
FFGMPD
MAZ000-NHZ000-VTZ000-CTZ000-NYZ000-NJZ000-PAZ000-090230-

Mesoscale Precipitation Discussion 1042
NWS Weather Prediction Center College Park MD
542 PM EDT Fri Sep 08 2023

Areas affected...portions of eastern PA...northern and central
NJ...southern NY...southern VT...southwestern NH...western
MA...western CT

Concerning...Heavy rainfall...Flash flooding possible

Valid 082140Z - 090230Z

Summary...Additional localized totals of 1-3" through evening may
lead to isolated instances of flash flooding

Discussion...Showers and thunderstorms have proliferated across
portions of the Mid-Atlantic and New England this afternoon, in
the vicinity of a coastal warm front slowly progressing inland.
The mesoscale environment is characterized by SB CAPE of 1000-2500
J/kg, PWATs of 1.5-1.8" (between the 90th percentile and max
moving average, per OKX/ALB sounding climatology), and effective
bulk shear of 20-30 kts. While isolated storm totals through 21z
have generally ranged between 1-2" (per MRMS estimates and
available observations), there have been a few localized totals as
high as 3-6". These more extreme totals have generally been
associated with cell mergers and collisions, as convection so far
this afternoon has generally been disorganized in the vicinity of
the surface front. Deep layer (850-300 mb) mean flow towards the
northeast near 20 kts will continue to favor progressive
convection and limited hourly totals, but additional cell mergers
(and some back-building of convection) may lead to additional
accumulations of 1-3" through evening. Isolated instances of flash
flooding are considered possible, especially if heavy rainfall
occurs over urban terrain and poor drainage areas along the I-95
corridor. Some flash flooding could be significant, particularly
if additional 1-3" totals overlap with areas of prior heavy
rainfall.

Churchill

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!_Qz_u8KAA5_03AKK7PXq0icEXr_nzEYDRjqQ22NFuLaBk7BrZDzZIt7zsc_3bidPFkPF=
1zqN8xP3CY2upmV-eZwA6nc$  for graphic product...

ATTN...WFO...ALY...BGM...BOX...BTV...CTP...GYX...OKX...PHI...

ATTN...RFC...MARFC...NERFC...NWC...

LAT...LON   43687275 43387157 42347185 41757244 41027334=20
            40007459 40177556 40937590 41797569 42747484=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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